WO2013023585A1 - Continuous process for large-scale production of calcium sulfate whisker - Google Patents

Abstract

Disclosed is a continuous process for large-scale production of calcium sulfate whisker, which solves the problem that the current large-scale production of calcium sulfate whisker cannot be produced continuously. Large-scale continuous synthesis of calcium sulfate whisker may be achieved by the present invention by following five basic requirements for production of calcium sulfate whisker, namely, diluted solution, stable salt content, low rate, uniform stirring, long aging (time), and modified conditions for synthesizing the calcium sulfate crystal. The present invention further reduces the manual workload and lowers the technical requirements, and has unique advantages of being simple, high efficient, energy saving and environmental friendly, and excellent quality of whisker.

Description

 Continuous process method for large-scale production of calcium sulfate whiskers

 The present invention relates to a process for producing calcium sulfate whiskers, and more particularly to a process for the continuous commercialization of large-scale production of calcium sulfate whiskers. Background technique

 In the patent application file "A New Method for Mass Production of Calcium Sulfate Whisker" (Publication No. 101168852A), the technical solution includes the following steps:

a preparing a solution containing water-soluble Ca ²⁺ ; (including mixing a mixed acid with HCl, HNO ₃ , H ₃ P 0 ₄ or any ratio thereof, and decomposing the phosphorus-containing mineral to prepare a solution containing water-soluble Ca ²⁺ ;

b. preparing a solution containing water-soluble SO/-; (a solution containing H ₂ S0 ₄ ;)

c. purifying the above water-soluble Ca ²⁺ and S0 ₄ ² — respectively, and storing them separately;

d. using a solution of purified water-soluble Ca ²⁺ and SO/-, respectively, to prepare a preparation solution for synthesizing calcium sulfate whiskers;

e, adding the SO/-containing solution and the Ca ²⁺ -containing solution to the whisker synthesizer, the product after the reaction comprises calcium sulfate whiskers, and aging, separating the calcium sulfate whiskers;

 f. Separating the calcium sulfate whiskers, washing them into a wet product of calcium sulfate whiskers, and returning the filtrate to the steps of steps 1, 1, b, c, d, etc. at any ratio, and discharging the liquid products at any time. The efflux liquid product is withdrawn for the recovery of high value components or for the use of such filtrate.

The advantage of this technology is that the raw materials are cheap, the process is simple, the equipment investment is small, the investment scale can be large or small and easy to expand. The main expansion link is step e, that is, the quantity and total volume of the whisker synthesizer are used to control the output. In the steps a, b, c, d, f, continuous flow can be realized, and only step e cannot continuously flow. The basic requirements for the production of calcium sulfate whiskers are thin solution, stable salt, slow, well-mixed, and aged (time). The dilution of the solution and the stabilization of the salt content can be completed by the step d continuous, but into the whisker synthesizer, the whisker crystallites must be grown in the SO/-excess state, so the SO/-containing solution must be added first. Adding a solution containing Ca ²⁺ , and controlling the reaction rate to be slow, the stirring is uniform, the aging time is longer under intermittent stirring, the reaction is terminated for solid-liquid separation, and the operation of synthesizing calcium sulfate whiskers is completed, and then The next cycle of synthesis of calcium sulfate whiskers. This intermittent operation method brings a lot of inconvenience to large industrial production:

1. Adding or discharging liquid to the whisker synthesizer is manual operation, requiring operators; intermittent operation cycles are different. It is easy to cause the whisker aspect ratio to fluctuate greatly;

2. Since the whisker synthesizer undergoes a process in which the concentration of SO/- is gradually decreased from high to high during each cycle, SO/- is adsorbed on both the synthesizer wall and the agitator when the concentration of SO/- is high, and Ca ^{2+ is} added. After the compounding liquid, the Ca ^{2+ is} easily formed with SO/—salt calcium sulfate whisker adsorbed on the wall of the vessel, the blade of the agitator, and the blade shaft, and is easily formed into a large piece of gypsum. Influencing the quality of whiskers, only by manual removal in time to ensure the quality of whiskers;

3. The filtrate after separating the calcium sulfate whiskers at the same time returns to steps a, b, c, and d at any ratio. For the filtrate returning to step a, SO/- must be excluded. For the filtrate returning to step b, Ca is not required. ²⁺ , only when the concentration of SO/- and Ca ²⁺ in the filtrate is equal to the solubility product, the quality standard of returning steps a, b, c, d can be satisfied, otherwise it is easy to step a and step b The formation of calcium sulphate crystals, manual control of the quality of the filtrate requires high difficulty. Summary of the invention

 SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and to provide a continuous process for producing calcium sulfate whiskers on a large scale.

 The technical solution adopted by the present invention includes the following steps:

a, preparing a solution containing water-soluble Ca ²⁺ ;

 b. preparing a solution containing water-soluble SO/-;

c. respectively purifying the above water-soluble Ca ²⁺ and SO/- solutions to prepare a Ca ²⁺ purification liquid and a SO/-purification liquid, and storing them separately;

 D_l, continuously preparing SO/-mixing liquid with dilute solution containing SO/- and SO/-purifying liquid;

D_2, continuously preparing a Ca ²⁺ solution by using a dilute solution containing Ca ²⁺ and a Ca ²⁺ purification solution;

E_l, continuously adding the SO/-containing compounding liquid and the Ca ²⁺ -containing compounding liquid to the whisker synthesizer, and controlling the mixed reaction product to contain an excessive amount of SO/-dilute solution and calcium sulfate Whiskers

 E_2, continuously transferring the product containing excess SO/-diluted solution and calcium sulfate whisker into the aging thickener; e-3, the calcium sulphate whisker in the aging thickener is containing excessive SO / - Continuous aging under dilute solution conditions;

E_4, after separating a part of the aged calcium sulfate whisker from the aging thickener, containing an excessive amount of SO/-diluted solution, continuously feeding it into the storage reserve pool to form a dilute solution of SO/-, and the rest continuously Returning to step d-1; e_5, continuously separating the solid-liquid mixture including the aged calcium sulfate whisker and the SO/-diluted solution from the thickener, and continuously feeding it to the calcium-enhancing Ca ^{2 +} thickener; E_6, in the calcium-enhanced Ca ²⁺ thickener, continuously adjust the concentration of calcium ion Ca ²⁺ in the thickener with Ca ²⁺ purification solution, so that the calcium sulfate whisker is in a dilute solution condition containing calcium ion Ca ²⁺ excess Continuously aging, and continuously discharging the aged solid-liquid compound out of the calcium-enhancing Ca ²⁺ thickener;

f. Calcium sulphate whiskers from a calcium-enhanced Ca ²⁺ thickener, filtered and washed to form a wet product of calcium sulphate whiskers; a filtrate containing excess calcium ion Ca ²⁺ , separated and sent to a storage reserve tank to form A dilute solution of Ca ²⁺ , the remainder is continuously returned to step d-2. The preparation of the solution containing water-soluble Ca ²⁺ prepared in step a is prepared by using a dilute solution of Ca ^{2+ in} a reserve pool.

 The preparation of the solution containing the water-soluble SO/- prepared as described in the step b is prepared by using a SO/-diluted solution for storing the reserve tank.

 The purification described in the step C is carried out by sedimentation, filtration, adding a special ion-removing reagent to form a special precipitate to be extracted, adsorbing, etc.; or by adding a substance for adjusting the pH value to separate a certain type of ions for purification. The pH-adjusting substance to be added is an ore and mineral powder containing phosphorus, or limestone, lime milk or the like containing calcium.

The preparation of the SO/-mixing liquid described in the step d-1 includes adding an acid, a base, a salt, an organic substance or the like as a whisker controlling agent, so that the H ⁺ ion concentration of the SO/-mixing liquid is 20 mol/L ^10-12 mol/ between L; S0 ₄ ² - temperature regulating liquid formulation between -20~120 ° C, the concentration is preferably 0. 2~2 mol / L.

The whiskers control agents, include various organic and inorganic compounds, wherein the inorganic acid is _{HC1, HN0 3, H 3 P0} 4 and the like; organic acids are formic acid, acetic acid, fatty acids, alcohols and the like; an inorganic salt containing K ⁺ Water-soluble phosphate, chloride and nitrate of cations such as Na\NH ₄ \ Mg ²⁺ , ΑΓ, Mn ²⁺ ; organic substances comprising water-soluble alkyl fatty acid salts, alkylbenzene sulfonates, polyvinyl alcohol , a polyacrylamide surfactant; the base is a compound containing 0H_, including Mg (0H) ₂ .

The preparation of the Ca ²⁺ -mixing solution described in the step d-2 includes adding an acid, a base, a salt, an organic substance or the like as a whisker controlling agent, so that the H ⁺ ion concentration of the Ca ²⁺ compounding solution is 20 mol/L to ^10-12 mol. between / L; Ca ²⁺ - a temperature regulating liquid formulation between -20~120 ° C, the concentration is preferably 0. 2~2 mol / L.

The whisker control agent includes various organic and inorganic compounds, wherein the inorganic acid comprises HC1, HNO ₃ , P0 _{4 ,} etc.; the organic acid comprises formic acid, acetic acid, a fatty acid, an alcohol, etc.; and the inorganic salt contains K _{^{+, Na \ NH 4 \ Mg}} 2+, Α, water-soluble phosphate and the like Mn ²⁺ cations, chloride and nitrate; organic substance is a water soluble alkyl fatty acid salts, alkyl benzene sulfonates, polyvinyl alcohol , a polyacrylamide surfactant; the base is a compound containing 0H_, Includes Mg (0H) ₂ .

 O. 2〜3. 3 mol / L。 The concentration of SO / - is preferably 0. 02~0. 3 mol / L. The aging thickener described in the step e-2 comprises a thickening unit consisting of a split container, which respectively performs three functions of solid-liquid residence time, dense fluid discharge and clarified liquid discharge.

 The diluted aging solution of the storage reserve pool described in step e-4 is preferably 0. 5~5 hours; Including liquids containing water-soluble metal ions

^z: mouth

Wide PR o

The calcium-increasing Ca ²⁺ thickener described in the step e-5 comprises a concentrated unit composed of a split container, and respectively performs three functions of solid-liquid residence time, dense fluid discharge, and clarified liquid discharge.

E-6 with the step of cleaning fluid continuous regulation of Ca ²⁺ ions Ca ²⁺ concentration of calcium in the calcium thickener increases, the concentration of calcium ions Ca ²⁺ regulation in the preferred 0. 02~1. 0 mole / liter 5〜5小时。 The time of aging is preferably 0. 5~5 hours.

The dilute solution of Ca ²⁺ in the storage reserve tank described in step f is a liquid product including water-soluble metal ions.

The water-soluble Ca ²⁺ solution described in step a includes:

1) using a mixed acid of HCl, HN0 ₃ , H ₃ P0 ₄ or any combination thereof, to decompose the phosphorus-containing mineral to prepare a solution containing water-soluble Ca ²⁺ ;

2) water-soluble CaCl ₂ containing NaCl effluxed by an ammonia-based process _;

3) a water-soluble Ca ²⁺ solution prepared by reacting a spent acid solution in a pickling and derusting industry with a calcium-containing compound such as lime milk, quicklime or limestone;

4) a water-soluble Ca ²⁺ solution prepared by pickling ore (mineral powder) of precious metal processing industry;

5) a water-soluble Ca ²⁺ solution prepared from an organic or inorganic spent acid and a calcium-containing compound;

6) containing water-soluble solids with Ca ^2+, and with an aqueous solution of a water-soluble Ca ²⁺ was prepared;

 The solution containing the water-soluble SO/- described in step b includes:

 1) an SO/-solution containing SO/-water-soluble solids dissolved in an aqueous solution;

2) a salt solution containing N3⁄4S0 ₄ component;

3) a salt solution containing a K ₂ S0 ₄ component;

4) an acid salt solution containing HS0 ₄ - component;

5) a solution containing H ₂ S0 ₄ ;

6) SO/containing containing solid matter containing CaS0 ₄ component and ammonium salt containing C0 ₃ ² -component Ammonium salt solution;

7) A water-soluble SO ₄ ² _ solution formed by reacting a solid matter containing a CaS0 ₄ component with a sodium salt containing a C0 ₃ ² component. BRIEF abstract

 The drawings are schematic flow diagrams of the process principle of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

 Detailed description of the invention

 The technical solution adopted by the present invention includes the following steps:

a, preparing a solution containing water-soluble Ca ²⁺ ; this step in the continuous production, mainly to protect two, one is that the solution of dissolved Ca ²⁺ does not contain SO / - ions, the present invention is used to store spare Ca The dilute solution of ²⁺ is prepared; the second is the source of the water-soluble Ca ²⁺ solution to ensure that the present invention is preferably a raw material that satisfies the needs of large industrial production. Preferred water soluble Ca ²⁺ solutions of the invention include:

1) using a mixed acid of HCl, HN0 ₃ , H ₃ P0 ₄ or any combination thereof, to decompose the phosphorus-containing mineral to prepare a solution containing water-soluble Ca ²⁺ ;

2) water-soluble CaCl ₂ containing NaCl effluxed by an ammonia-based process _;

3) a water-soluble Ca ²⁺ solution prepared by reacting a spent acid solution in a pickling and derusting industry with a calcium-containing compound such as lime milk, quicklime or limestone;

4) a water-soluble Ca ²⁺ solution prepared by pickling ore (mineral powder) of precious metal processing industry;

5) a water-soluble Ca ²⁺ solution prepared from an organic or inorganic spent acid and a calcium-containing compound;

6) containing a water-soluble Ca ²⁺ solids, prepared with an aqueous solution of a water-soluble Ca ²⁺ solution.

b. Preparing a solution containing water-soluble SO/-; this step also ensures two in continuous production. First, the SO/-dissolved solution does not contain Ca ²⁺ ions, and the present invention is used for storage. The source of the SO/-containing dilute solution is prepared; the second is the source of the water-soluble SO/-solution to ensure that the present invention is preferably a raw material that satisfies the requirements of large industrial production. Preferred solutions comprising water soluble SO/- according to the invention include:

 1) an SO/-solution containing SO/-water-soluble solids dissolved in an aqueous solution;

2) a salt solution containing N3⁄4S0 ₄ component;

3) a salt solution containing a K ₂ S0 ₄ component;

4) an acid salt solution containing HS0 ₄ - component; 5) a solution containing H ₂ S0 ₄ ;

6) an SO/-containing ammonium salt solution formed by reacting a solid matter containing a CaS0 ₄ component with an ammonium salt containing a C0 ₃ ² -component;

7) A water-soluble SO ₄ ² _ solution formed by reacting a solid matter containing a CaS0 ₄ component with a sodium salt containing a C0 ₃ ² component.

c. Purifying the above water-soluble Ca ²⁺ and SO/- solutions separately, preparing Ca ²⁺ purification liquid and SO/-purification liquid, and storing them separately for use; the purification of the step is by sedimentation, filtration, adding and removing special ions. The reagent generates a special precipitate to be purified by extraction, adsorption, or the like; or is added by adjusting a pH value to separate a certain type of ion, and the added pH-adjusting substance is an ore containing phosphorus and Mineral powder, or limestone, lime milk, etc. containing calcium. The basic requirement is that the solution should be clarified and contain no harmful impurities that affect the quality of the calcium sulfate whisker product.

Dl, step d-1 to prepare SO / - compounding solution includes: continuously preparing SO / - liquid mixture with SO / - dilute solution and SO / - purification liquid; adding acid, alkali, salt, organic matter, etc. as whisker control The H ⁺ ion concentration of the SO/-mixing solution is between 20mol/L and ^10-12 mol/L; the temperature of the S0 ₄ ² -mixing solution is adjusted between -20 and 120 ° C; S0 ₄ ² — 2〜2摩尔/L。 The concentration of the solution is preferably 0. 2~2mol / L.

The whisker controlling agent comprises various organic and inorganic compounds, wherein the inorganic acid is HC1, HNO ₃ , H ₃ P0 _{4 ,} etc.; the organic acid is formic acid, acetic acid, fatty acid, alcohol, etc.; the inorganic salt contains K ⁺ Water-soluble phosphate, chloride and nitrate of cations such as Na\NH ₄ \ Mg ²⁺ , ΑΓ, Mn ²⁺ ; organic substances are water-soluble alkyl fatty acid salts, alkylbenzene sulfonates, polyvinyl alcohol, A surfactant such as polyacrylamide; the base is a compound containing 0H_, including Mg(0H) ₂ .

D-2, step d-2 to prepare Ca ²⁺ - the formulation solution comprises: continuously preparing a Ca ²⁺ solution with a dilute solution containing Ca ²⁺ and a Ca ²⁺ purification solution; adding acid, alkali, salt, organic matter, etc. Whisker control agent; the H ⁺ ion concentration of the Ca ²⁺ solution is between 20mol/L and ^10-12 mol/L; the temperature of the quantification tank is adjusted between -20 and 120 ° C; Ca ²⁺ - blending 2〜2摩尔/L。 The concentration of the liquid is preferably 0. 2~2mol / L.

The whisker controlling agent comprises various organic and inorganic compounds, wherein the inorganic acid is HC1, HNO ₃ , H ₃ P0 _{4 ,} etc.; the organic acid is formic acid, acetic acid, fatty acid, alcohol, etc.; the inorganic salt contains K ⁺ Water-soluble phosphate, chloride and nitrate of cations such as Na\NH ₄ \ Mg ²⁺ , ΑΓ, Mn ²⁺ ; organic substances are water-soluble alkyl fatty acid salts, alkylbenzene sulfonates, polyvinyl alcohol, A surfactant such as polyacrylamide; the base is a compound containing 0H_, including Mg(0H) ₂ .

In the prior art "A New Method for Mass Production of Calcium Sulfate Whisker" (Publication No. 101168852A), in the prior art, only step e cannot continuously perform the flow operation. The basic requirement for the production of calcium sulfate whiskers is the solution Dilute, salty, slow, well-mixed, aged (time) long. In steps dl, d-2, it is solved that the solution is dilute and the salt is stable. The present invention is required to complete the steps of slow speed, stirring, and aging (time) in step e, especially when generating calcium sulfate whiskers. The "germination period" must maintain SO / - excess. Therefore, the step e of the prior art is expanded to 6 steps in the present invention.

E_l, continuously adding the SO/-containing compounding liquid and the Ca ²⁺ -containing compounding liquid to the whisker synthesizer, and controlling the mixed reaction product to contain an excessive amount of SO/-dilute solution and calcium sulfate Whisker; The concentration of excess SO/- is preferably 0. 02~0. 3 mol/L, which is the basic condition for ensuring the growth of calcium sulfate whiskers in the "germination period".

 E_2, continuously transferring the product containing excess SO/-diluted solution and calcium sulfate whisker into the aging thickener; using the thickener aging, the solid-liquid residence time can be determined by designing the volume and cross-sectional area of the thickener; The dense fluid discharge and clarified liquid discharge can be determined by the growth rate and settling speed of the calcium sulfate whiskers; these three functions include the use of a dense unit consisting of separate vessels to complete the solid-liquid residence time, dense fluid discharge, and clarified liquid discharge. These three functions.

 The aging time is preferably 0.5 to 5 hours. The aging time is preferably 0.5 to 5 hours.

 The steps e-l, e-2, and e-3 of the present invention are the most critical steps in the formation of whiskers and aged whiskers.

E_4, after separating a part of the aged calcium sulfate whisker from the aging thickener, containing an excessive amount of SO/-diluted solution, and continuously feeding it into the storage reserve pool to form a dilute solution of SO/-; The SO/-diluted solution is a liquid product comprising a water-soluble metal ion; the link is a node of the continuous process flow of the present invention, in which a dilute solution containing SO/- is dispensed for Formulating a solution containing SO/-, such a Ca ^{2+ -free} dilute solution does not form calcium sulphate crystals; second, the present invention is a circulatory system in which various water-soluble components entering from step a or step b are circulated From the continuous accumulation, especially the metal ions that need to be recovered, the circulating liquid product can be continuously or intermittently discharged from this outlet.

E_5, continuously separating a solid-liquid mixture containing both aged calcium sulfate whiskers and a dilute solution containing SO/- from a thickener, and continuously feeding it to a calcium-enhancing Ca ²⁺ thickener.

Calcium-enhanced Ca ²⁺ thickeners, including dense units consisting of split containers, perform three functions: solid-liquid residence time, dense fluid discharge, and clarified liquid discharge. The calcium-calcifying Ca ²⁺ thickener is selected in the same manner as in step e-2. The purpose of the calcium-calcium whisker is to prepare a solution containing calcium ion Ca ²⁺ after the growth period is completed. The SO/ in the solution is completely precipitated with a solution containing calcium ion Ca ²⁺ . Since the solution containing SO/- is very thin, when reacted with a solution of calcium ion Ca ²⁺ , the CaS0 ₄ crystal formed is attached to the sulfuric acid. On the large crystal of calcium whiskers, no new fine crystals are formed, and even if fine crystals are formed, fine knots can be formed in aging. Crystal dissolution, which promotes the further increase of calcium sulfate whiskers with large particle size, is the basic law of crystal growth. The purpose of this step is to complete the conversion of SO/- to Ca ²⁺ in the solution to facilitate the use of the solution.

E_6, in the calcium-enhanced Ca ²⁺ thickener, continuously adjust the concentration of calcium ion Ca ²⁺ in the thickener with Ca ²⁺ purification solution, so that the calcium sulfate whisker is in a dilute solution condition containing calcium ion Ca ²⁺ excess 0摩尔/升。 The aging of the aging, the aging of the solid-liquid compound is continuously discharged from the calcium-enhanced Ca ²⁺ thickener, and the concentration of the calcium ion ²⁺ is adjusted to 0. 02~1. 5〜5小时。 The time of aging is preferably 0. 5~5 hours.

In step e-5, e-6, the conversion of S0 ₄ ² - to Ca ²⁺ in the solution is completed, and the solid-liquid mixture of the calcium-enriched Ca ²⁺ thickener is discharged, which is the crystallized calcium sulfate crystal after completion of the aging period. A product and a calcium-containing solution that requires further use. The present invention uses this calcium-containing solution in two categories: one for the present cycle system and the other for the liquid product discharge circulatory system.

f. Calcium sulphate whiskers from a calcium-enhanced Ca ²⁺ thickener, filtered and washed to form a wet product of calcium sulphate whiskers; a filtrate containing excess calcium ion Ca ²⁺ , separated and sent to a storage reserve tank to form A dilute solution of Ca ²⁺ , this kind of storage liquid has two kinds of uses: First, it is used in the circulation system, especially the one flow direction which is the largest amount is continuous return step d-2 is used to prepare Ca ²⁺ - preparation liquid. Second, because the solution includes water-soluble metal ions, it can be discharged as a liquid product to the circulation system.

 The beneficial effects of the invention:

 1. The present invention is based on the prior art disclosed in "A New Method for Large-Scale Production of Calcium Sulfate Whisker" (Publication No. 101168852A), which simplifies the inadequacy of the original process step e incapable of continuous flow operation. According to the basic requirements that must be followed in the production of calcium sulfate whiskers: dilute solution, stable salt, slow speed, uniform mixing, long aging (time), improved synthesis of calcium sulfate crystals, and its large-scale continuous synthesis Calcium sulfate whisker, therefore, the invention not only completely retains all the advantages and benefits of the prior art, but also further reduces the manual operation workload and reduces the technical requirements, thereby producing a large number of higher quality calcium sulfate whiskers. .

2. Due to the high-yield, high-margin product of calcium sulfate whisker and the large-scale, high-efficiency, low-energy production method, various materials containing water-soluble Ca ²⁺ and SO/-, including water-insoluble but After chemical reaction, it can be converted into water-soluble materials, which can be used with high efficiency.

 3. The present invention has a unique advantage in improving and changing some of the current large-scale industrialized processes with serious pollution, high waste, high energy consumption, and low efficiency, namely, low investment, low cost, and high economic efficiency. It not only provides the society with a large number of excellent environmentally friendly calcium sulfate whisker products, but also eliminates environmental pollution in these processes.

4. The present invention theoretically and practically describes a continuous process for the large-scale production of calcium sulfate whiskers, and more fully embodies the unique advantages of the invention, such as simplicity, high efficiency, energy saving, environmental protection, and excellent whisker quality. Example 1: The present invention continuously produces calcium sulfate whiskers in the process of preparing phosphate products from acid phosphate rock

(See the schematic diagram of the process flow principle)

 IMPLEMENTATION OBJECT: This example is in the prior art of a new method for mass production of calcium sulfate whiskers (Publication No. 101 168852A), which fails to continuously streamline the original process step e. Improve it. According to the basic requirements that must be followed in the production of calcium sulfate whiskers: dilute solution, stable salt, slow speed, uniform mixing, long aging (time), improved conditions for the synthesis of calcium sulphate crystals, while producing phosphorus products , calcium sulfate whiskers can be synthesized on a large scale continuously.

 Process steps of this embodiment:

a. preparing a solution comprising water-soluble Ca ²⁺ ;

The phosphate rock enters the acid solution pool and mixed with HN0 ₃ , HC1 , H ₃ P0 ₄ or any proportion thereof (and the organic acid in the phosphate rock raw material and the artificially added organic acid, etc., the artificial addition of the organic acid is the synthesis of whiskers When the whisker characteristics are controlled, the reaction is carried out to form an acid hydrolyzate containing water-soluble Ca ²⁺ and phosphoric acid, and the phosphate rock and the phosphoric acid are continuously reacted to form a calcium dihydrogen phosphate precipitate to achieve dephosphorization (see the inventor's acid). Method for dephosphorization ore" Publication No. CN1962421A); The solution after dephosphorization contains water-soluble Ca ²⁺ ions, which are sedimented, filtered and placed in a Ca ²⁺ containing storage tank to form a solution containing water-soluble Ca ²⁺ ;

 b. preparing a solution containing water-soluble SO/-;

Preparing a solution containing water-soluble SO/- using a raw material containing S0 ₄ ;

c. respectively purifying the above water-soluble Ca ²⁺ and SO/- solutions to prepare a Ca ²⁺ purification liquid and a SO/-purification liquid, and storing them separately;

 D_l, continuously prepare SO/-mixing solution with the SO/-containing dilute solution and SO/-purifying liquid (first use of clean water);

D_2, continuously prepare a Ca ²⁺ solution with a dilute solution containing Ca ²⁺ and a Ca ²⁺ purification solution (first use of clean water); e_l, a solution containing SO/- and a formulation containing Ca ²⁺ Continuously added to the whisker synthesizer to control the product after the mixing reaction to contain an excess of SO/-diluted solution and calcium sulfate whisker;

 E_2, continuously transferring the product containing the excess SO/-diluted solution and calcium sulfate whisker into the aging thickener; e-3, the calcium sulphate whisker in the aging thickener is containing an excessive amount of SO / - Continuous aging under dilute solution conditions;

E_4, after separating a part of the aged calcium sulfate whisker from the aging thickener, containing an excessive amount of SO/-diluted solution, continuously feeding it into the storage reserve pool to form a dilute solution of SO/-, and the rest continuously Return to step d-1; E_5, continuously separating from the thickener a solid-liquid mixture comprising both aged calcium sulfate whiskers and a dilute solution containing SO/-, and continuously feeding it to a calcium-enhancing Ca ²⁺ thickener;

E_6, in the calcium-enhanced Ca ²⁺ thickener, continuously adjust the concentration of calcium ion Ca ²⁺ in the thickener with Ca ²⁺ purification solution, so that the calcium sulfate whisker is in a dilute solution condition containing calcium ion Ca ²⁺ excess Continuously aging, and continuously discharging the aged solid-liquid compound out of the calcium-enhancing Ca ²⁺ thickener;

f. Calcium sulphate whiskers from a calcium-enhanced Ca ²⁺ thickener, filtered and washed to form a wet product of calcium sulphate whiskers; a filtrate containing excess calcium ion Ca ²⁺ , separated and sent to a storage reserve tank to form A dilute solution of Ca ²⁺ (return to step a for the next cycle of acid phosphate rock) and the remainder is returned to step d-2.

This embodiment is a high-efficiency method for fully utilizing phosphate rock and S0 ₄ , and is suitable for the raw material of the ammonium sulfate ammonium sulfate process. A new method for mass production of calcium sulfate whiskers has been disclosed (Publication No. 101168852A) In the prior art, this embodiment improves the inadequacy of the original process step e incapable of continuous flow operation. It enables the synthesis of calcium sulfate whiskers on a large scale while producing phosphorus products.

In particular, when HN0 ₃ is used as the circulating medium, that is, the introduction of H ₂ S0 ₄ raw material by ammonium phosphate ammonium or the introduction of nitric acid into the circulating medium by ammonium phosphate, this method can clearly demonstrate the full advantages of the two ammonium phosphate processes, and Fundamentally, in addition to the various defects of the current ammonium phosphate, various high, medium and low grade phosphate rock can be directly used to produce ammonium phosphate with excellent quality and extremely high purity pure calcium sulfate whisker. Example 2 The invention combines the production of calcium sulfate whiskers on the basis of the sulfur-based compound fertilizer process

Purpose of implementation: Sulfur-based compound fertilizer is an excellent compound fertilizer variety, but with the expansion of production scale, not only can not eliminate the five major defects inherent in the ammonium phosphate process, but how to deal with the high concentration of hydrochloric acid by-produced, this has become a constraint on sulfur A major issue in the large-scale development of base compound fertilizers. Because the sulfur-based compound fertilizer process by-product HC1 (gas), water absorption is hydrochloric acid, the invention uses an acid hydrolysis solution to absorb HC1 gas, and the saved water is further applied to the phosphogypsum ammonium sulfate process to obtain water-soluble solution. (NH ₄ ) ₂ · S0 ₄ , (NH ₄ ) ₂ * S0 ₄ and KC1 metathesis to K ₂ S0 ₄ is a mature current process, 80% of (NH ₄ ) ₂ S0 ₄ can be made into K ₂ S0 ₄ , Its large output, large value-added, and high efficiency, it is precisely this C1-free potash fertilizer has excellent agricultural benefits, which has become the driving force for the large-scale development of sulfur-based compound fertilizer. The chemical reaction applied by the present invention is:

Ca ₅ F (P0 ₄ ) +IOHCI (including KC1, NH4CI)

=3H ₃ P0 ₄ +5CaCl ₂ +HF (including KC1, NH ₄ C1 ) Formula (2-1)

25CaS0 ₄ · 2H ₂ 0 (pity gypsum) +25 (NH ₄ ) ₂ C0 ₃

=25CaC0 ₃ \ +25 (NH ₄ ) ₂ S0 ₄ (liquid) +50H ₂ 0 (2- 2 ) 25 (NH ₄ ) ₂ S0 ₄ (liquid) +50KC1 (solid)

=20K ₂ S0 ₄ (solid) +5K ₂ S0 ₄ (liquid) +50NH ₄ C1 (liquid) formula (2-3)

3H ₃ P0 ₄ +5CaCl ₂ +5K ₂ S0 ₄ +50NH ₄ Cl

=5CaS0 ₄ · 2H ₂ 0 (high-purity whiskers) +3H ₃ P0 ₄ +10KC1+40NH ₄ C1 Formula (2- 4) 3H ₃ P0 ₄ + 1 OKC 1 +50NH ₄ C 1 +3NH ₃

=3NH ₄ H ₂ P0 ₄ +10KC1+50NH ₄ C1 (combined fertilizer raw material into ammonium phosphate process) The general material reaction of formula (2-5) to formula (2-1) to formula (2-5) is:

 Raw materials:

Ca ₅ F (P0 ₄ ) +IOHCI (gas) +25CaS0 ₄ · 2H ₂ 0 (phosphorus gypsum) +25 (NH ₄ ) ₂ C0 ₃ +50KC1+3NH ₃

≠n mouth

 Wide pm:

20K ₂ S0 ₄ solid +5 CaS0 ₄ · 2 H ₂ 0 whisker + ( 3NH ₄ H ₂ P0 ₄ + 1 OKC 1 +50NH ₄ C 1 ) +25CaC0 ₃

 Example process steps:

a, preparing a solution containing water-soluble Ca ²⁺ ;

High concentration of HC1 solution (for the first time) Add to the acid hydrolysis tank containing phosphate rock (raw ore) to form an acid hydrolysis solution containing water-soluble Ca ²⁺ and phosphoric acid, and the acid hydrolysis solution (including the first reaction with phosphate rock and phosphoric acid) The precipitate of the calcium dihydrogen phosphate is formed to achieve dephosphorization (see the inventor's method for the acid hydrolysis of phosphate rock, published in the number CN1962421A), after sedimentation, filtration, and into the Ca ²⁺ reservoir, and the acid hydrolysis solution is maintained. ~0. 5mol / L of excess HC1, the preliminary purified solution contains water-soluble Ca ²⁺ ions, placed in a Ca ²⁺ containing storage tank, into a solution containing water-soluble Ca ²⁺ ;

 b. preparing a solution containing water-soluble SO/-;

A phosphogypsum and press _{CaS0 4 · 2 ¾0 (NH 4} ) 2 C0 3: 2 C0 3 molar ratio of ₍₄ NH) is 1. 05~1 · 1: 1 ratio was added carbonation reactor at 30~80 ° C The reaction is carried out at a temperature, and the (NH ₄ ) ₂ S0 ₄ supernatant is filtered out and added to the metathesis reactor. KC1 is added in a theoretical amount of (NH ₄ ) ₂ S0 ₄ + ₂ KC1, and reacted at 50 to 80 ° C to separate K. ₂ S0 ₄ process, the K ₂ S0 ₄ solid matter is separated, the filtrate contains water-soluble K ₂ S0 ₄ and NH ₄ C1 solution, and the filtrate is placed in a SO/—, NH ₄ C1 solution tank to cool down to room temperature, and the SO is filtered out through a filtering device. L〜10摩尔/l范围内。 The liquid is added to the SO / - storage tank, and the addition of HC1 to the tank, so that the H ⁺ concentration in the range of 0. l~10mol / l. This is a solution containing water-soluble S0 ₄ ² — NH ₄ C1;

C, respectively, with the above purifying water-soluble Ca ²⁺ and SO / - solution, the decontamination liquid is made of Ca ²⁺ and S0 ₄ ² - cleaning fluid, respectively, and stored for later use;

 D_l, continuously preparing SO/-mixing liquid with dilute solution containing SO/- and SO/-purifying liquid;

D_2, continuously preparing a Ca ²⁺ solution by using a dilute solution containing Ca ²⁺ and a Ca ²⁺ purification solution;

E_l, continuously adding the SO/-containing solution and the Ca ²⁺ -containing solution to the whisker synthesizer, controlling Mixing the reacted product to contain an excess of so/-dilute solution and calcium sulfate whisker;

 E_2, continuously transferring the product containing the excess SO/-diluted solution and calcium sulfate whisker into the aging thickener; e-3, the calcium sulphate whisker in the aging thickener is containing an excessive amount of SO /- Continuous aging under dilute solution conditions;

E_4. After separating a portion of aged calcium sulfate whiskers from the aging thickener, an excess of S0 ₄ ² -diluted solution is included, which is continuously fed into a storage reserve tank to form a dilute solution of SO/-.

In the present embodiment, this is a solution containing no Ca ²⁺ , and the SO/- is very dilute. Preferably, the concentration of the SO/- ion is 0.05-0.2 mol/l, but the nitrogen of the solution, The total concentration of phosphorus and potassium is a nearly saturated solution. The chemical composition is: 3H ₃ P0 ₄ +10KC1+40NH ₄ C (see formula (2-4)). The ammonia is a ternary compound fertilizer, namely:

3H ₃ P0 ₄ + 10KC 1 +40 group 1 +3NH ₃

=3NH ₄ H ₂ P0 ₄ + 10KC 1 +40NH ₄ C 1 (complex fertilizer raw material which enters the ammonium phosphate process) Formula (2-5) Therefore, the liquid product of this embodiment is mainly conveyed from this outlet.

E_5, continuously separating from the thickener a solid-liquid mixture comprising both aged calcium sulfate whiskers and a dilute solution containing SO/-, and continuously feeding it to a calcium-enhancing Ca ²⁺ thickener;

E_6, in the calcium-enhanced Ca ²⁺ thickener, continuously adjust the concentration of calcium ion Ca ²⁺ in the thickener with Ca ²⁺ purification solution, so that the calcium sulfate whisker is in a dilute solution condition containing calcium ion Ca ²⁺ excess Continuously aging, and continuously discharging the aged solid-liquid compound out of the calcium-enhancing Ca ²⁺ thickener;

f. Calcium sulphate whiskers from a calcium-enhanced Ca ²⁺ thickener, filtered and washed to form a wet product of calcium sulphate whiskers; a filtrate containing excess calcium ion Ca ²⁺ , separated and sent to a storage reserve tank to form A dilute solution of Ca ²⁺ is returned to step d-2 in succession. Example 3: The invention is applied to the ammoniacal alkali process to co-produce calcium sulfate whiskers

 Implementation purpose:

The composition of ammonia-line effluent wastewater is about 10% of CaCl, about 5% of NaCl, 10~12m ^{3 of} wastewater discharged from soda ash, the utilization rate of salt in ammonia-alkali process is about 67%, the utilization rate of total raw materials is less than 30%, per ton of soda ash. 1 ton of pure CaCl _{2 is} effluxed. How to efficiently recover CaCl ₂ and NaCl in wastewater is a major research topic of ammonia-based process.

The invention utilizes the resource advantages of the ammonia-alkali plant and the advantages of the domestic sulfate mineral resources to be exploited and utilized, and by means of the water-soluble CaCl ₂ and the water-soluble sulfate, the high-quality calcium sulfate whisker is co-produced, and the ammonia-alkali is realized. Full recovery of effluent wastewater. Although the ammonia-based process itself has inherently low raw material utilization rates, high heat consumption, high investment, high operating costs, and serious pollution, it is not yet eradicated, but it can be used to increase production value and profit. The use of external "three wastes" and other methods to eradicate some of its parts can also significantly change the current ammonia-alkali process. The invention utilizes the sulphate mineral resources to realize the full recovery of CaCl ₂ in the external wastewater, thereby providing a high-efficiency way for 100% complete utilization of the raw materials.

Alkali as ammonia effluent NaCl and CaCl ₂ containing solution, (due to the presence of lime, PH> 8), the water-soluble sulfate (N _¾ from Salt Lake S0 ₄ + NaCl Γ¾ value generally greater than 8), prepared by reacting sulfuric acid Calcium whiskers.

 Example process steps:

a, preparing a solution containing water-soluble Ca ²⁺ ;

The ammonia-alkali plant generally has a large sedimentation tank, and the supernatant is filtered and placed in a Ca ²⁺ storage tank for use as a solution containing water-soluble Ca ²⁺ ;

 b. preparing a solution containing water-soluble SO/-;

 Using SO2-containing Glauber's salt, a mineral containing water-soluble sulfate, preparing an aqueous solution containing SO/-, chemically purifying (removing various impurities which are not conducive to the production of soda ash), mechanically filtering and putting it into a SO/-storage pool, a solution containing a water-soluble SO/-;

c. separately purifying the above solution containing water-soluble Ca ²⁺ and SO/-, preparing a Ca ²⁺ purification liquid and a S0 ₄ ² - purification liquid, and storing them separately;

 D_l, continuously preparing SO/-mixing liquid with dilute solution containing SO/- and SO/-purifying liquid;

D_2, continuously preparing a Ca ²⁺ solution by using a dilute solution containing Ca ²⁺ and a Ca ²⁺ purification solution;

E_l, continuously adding the SO/-containing compounding liquid and the Ca ²⁺ -containing compounding liquid to the whisker synthesizer, and controlling the product after the mixing reaction to contain an excessive amount of SO/-dilute solution and calcium sulfate Whiskers

 E_2, continuously transferring the solid-liquid compound containing an excessive amount of SO/-diluted solution and calcium sulfate whisker into the aging thickener;

 E-3. The calcium sulfate whisker in the aging thickener is continuously aged under the condition of containing an excessive SO/-dilute solution;

 E_4. After separating a part of the aged calcium sulfate whiskers from the aging thickener, an excessive SO/-thin solution is contained, and it is continuously sent to the storage reserve tank to form a SO/-diluted solution. In this embodiment, the SO/-diluted solution is mainly returned to the step b to prepare a water-soluble SO/- solution, and the step d-1 is continuously formulated with a SO/-containing dilute solution and a SO/-purifying liquid. /—The solution is prepared.

E_5, continuously separating from the thickener a solid-liquid mixture comprising both aged calcium sulfate whiskers and a dilute solution containing SO/-, and continuously feeding it to a calcium-enhancing Ca ²⁺ thickener;

E_6, continuously adjust the concentration of calcium ion Ca ²⁺ in the thickener with Ca ²⁺ purification solution in the calcium-increasing Ca ²⁺ thickener. Preferably, the concentration of Ca ²⁺ is 0. 05~0. 2mol/l, so that the calcium sulfate whisker is continuously aged under the condition of a dilute solution containing calcium ion Ca ²⁺ excess, and the solidified after aging The liquid compound continuously discharges the calcium-enhancing Ca ²⁺ thickener; f. the calcium sulfate whisker from the calcium-enriched Ca ²⁺ thickener, which is filtered and washed into a wet product of calcium sulfate whiskers; contains excessive calcium ions Ca ²⁺ The filtrate is separated and sent to a storage reserve tank to form a dilute solution of Ca ²⁺ , and the rest is continuously returned to step d-2.

In the present embodiment, a portion of the Ca ²⁺ solution is added to the storage pool. The chemical composition is about 15% NaCl, because the concentration of Ca ²⁺ is 0. 05 - 0. 2mol / l, this The solution can directly enter the ammonia-alkali process salt, so as to realize the complete recycling of the ammonia-line effluent wastewater, and theoretically produce the waste water discharged from the soda ash, and can produce 1.3 tons of high-purity anhydrous calcium sulfate whiskers. It can be seen that the potential economic benefits of the ammonia-alkali process are enormous. Example 4: The invention combines calcium sulfate whisker in an ammonium phosphate ammonium process

Purpose of implementation: Ammonium ammonium nitrate is a process for producing ammonium phosphate by decomposing phosphate rock with nitric acid. The process has a large amount of water-soluble Ca(N0 ₃ ) ₂ , but without SO/—, ammonium sulphate co-production of calcium sulfate whiskers must solve the SO/—source. The ammonium sulphate co-producing calcium sulphate whisker is only a high-quality industrial product, but the process change and impact brought to the ammonium phosphate process is much higher than the value of the product itself.

 The outstanding advantage of nitric acid decomposing phosphate rock is its strong adaptability to phosphate rock, from low-grade phosphate rock, high-grade phosphate rock to phosphorus-containing minerals containing many rare precious metals and extremely high recovery value. Characteristics, also for all kinds of heavy metals containing no phosphorus, precious metal ore, also have excellent solubility.

Regardless of the type of ore decomposed by nitric acid, it is inevitable that it is more or less water-soluble Ca ²⁺ . Nitric acid is a kind of high-value, high-priced, extremely versatile acid. There are huge raw material advantages and huge potential economic benefits. In most cases, the nitrate is decomposed with H ⁺ , because the nitrates produced are almost all water-soluble salts, and the high-grade nitric acid is used to decompose the phosphate rock to prepare low-grade agricultural ammonium phosphate, which obviously does not fully play the nitric acid. Raw material advantage. The focus of this embodiment is on how to use the product form of co-production of calcium sulfate whiskers to greatly increase the potential huge economic benefits of ammonium nitrate ammonium.

 The ammonium sulphate process combines the production of calcium sulphate whiskers in a variety of forms and flexibility.

1. Ca(N0 ₃ ) ₂ separated by the freezing process can be reacted with various sulfates containing K ⁺ , Na\ NH ₄ \ Mg ²⁺ , Zn ²⁺ , Cu ^{2+ ,} etc., in addition to preparing whiskers. Numerous high-quality nitrates, especially in combination with S0 ₄ , not only produce calcium sulfate whiskers, but also regenerate HN0 ₃ which decomposes phosphate rock. The H ⁺ price in sulfuric acid is low, which is both a raw material for preparing whiskers and a phosphorus decomposition. The mine offers H ⁺ , which is unrestricted in production investment and easy to produce.

2. When S0 ₄ ² — is provided by H ₂ S0 ₄ , the method of preparing Ca (H ₂ P0 ₄ ) ₂ · H ₂ 0 can be used (see <Acid Phosphorus) The method of mining, publication number CN1962421A), can also directly produce a mixture of high concentration of H ₃ P0 ₄ and a small amount of nitric acid or nitrate, directly into the process of ammoniation granulation, etc., not only can prepare a large amount of calcium sulfate whiskers, High quality ammonium phosphate or high quality decalcified, defluorinated Ca(H ₂ P0 ₄ ) ₂ * H ₂ 0 starting materials are also prepared to produce a range of high quality phosphates. This method has no refrigeration process, which can substantially simplify the ammonium phosphate process and increase the utilization rate of raw materials to 100% in theory.

3. Introducing H ₂ S0 ₄ raw materials on a large scale, fundamentally changing the current ammonium phosphate ammonium nitrate process. The current nitric acid used to decompose phosphate rock becomes a circulating medium, and its amount is mainly impurities other than calcium consumed in phosphate rock. On the ions (impurity ions other than calcium and SO/- can not form precipitates under acidic conditions, ie HN0 ₃ cannot be regenerated), due to the production of calcium sulfate whiskers, in high concentrations of H ₃ P0 ₄ and various near-saturated salts The produced calcium sulfate whiskers are extremely excellent, and the use, dosage, output, output value and profit of calcium sulfate whiskers are far greater than that of ammonium phosphate and various phosphorus products. Therefore, it is realized that the industrial products are mainly supplemented by agricultural products, and the workers and peasants have no "three wastes" high-efficiency factories. In theory, tons of HN0 ₃ can drive 20 tons to 30 tons of sulfuric acid to decompose phosphate rock, which is the current phosphorus nitrate. Ammonium production can be expanded by 20-30 times, and the profit margin is much higher than the separate ammonium nitrate ammonium process. Compared with HC1 as a circulating medium, ammonium phosphate products have no C1-ion. This production method is described in detail in Example 1 of the present invention.

In this run, or production need to purchase a large number of _304, in particular the large number of low concentrations of chemicals purchased byproduct H ₂ S0 ₄ when the H ₂ S0 ₄ dissolved in many organic chemicals, the use of such For H ₂ S0 ₄ , a small amount of concentrated HN0 ₃ (or other oxidizing agent, flocculant) is generally added to oxidize organic matter, which is ideally purified by sedimentation filtration, activated carbon adsorption, etc., for phosphorus products (Ca (H ₂ P0 ₄ ) ₂ * H ₂ 0 ) or concentrated H ₃ P0 _{4 has} no effect. This process accepts this low-concentration chemical by-product H ₂ S0 ₄ . Its major social significance is to use the raw material advantages and technological advantages of this process to save sulfur resources for the society. And promote the development of these chemical industries.

 Example process steps:

a, preparing a solution containing water-soluble Ca ²⁺ ;

 b. preparing a solution containing water-soluble SO/-;

1. When water-soluble Ca(N0 ₃ ) _{2 is} used as the calcium source, SO/- selects water-soluble sulfate, and especially industrial processing value is K ₂ S0 ₄ , N3⁄4S0 ₄ and the like which can generate high added value nitrate.

1. 1 Ca (N0 ₃ ) ₂ is dissolved into the sedimentation tank, filtered into Ca ²⁺ clear solution to be stored as a solution containing water-soluble Ca ²⁺ ;

1. 2 water-soluble sulfate (containing H ₂ S0 ₄ , KHS0 ₄ , K ₂ S0 ₄ , Na gas MgS0 ₄ , (NH ₄ ) ₂ S0 ₄ water-soluble sulfate), dissolved and filtered into SO / storage , to become a solution containing water-soluble SO / -;

2. Co-producing calcium sulfate whiskers by preparing Ca(H ₂ P0 ₄ ) ₂ · H ₂ 0. 2. 1 Phosphate ore and HN0 ₃ enter the acid hydrolysis tank to form an acid hydrolysis solution containing water-soluble Ca ²⁺ and phosphoric acid, and continue to react with phosphate rock and phosphoric acid to form calcium dihydrogen phosphate precipitate to achieve dephosphorization, and separate Ca (H) ₂ P0 ₄ ) ₂ 3⁄40 solid matter entering the phosphorus product process (see <Method for Acidolysis of Phosphate Rocks) Publication No. CN1962421A); solution after separating Ca (H ₂ P0 ₄ ) ₂ · H ₂ 0 solids contains water solubility Ca ²⁺ ions, after sedimentation, filtration, and placed in a Ca ²⁺ containing storage tank to form a solution containing water-soluble Ca ²⁺ ;

The acid hydrolysis solution of ammonium phosphate nitrate and the unpulverized phosphate rock may also be added to the acid hydrolysis tank. After 14 hours of acid hydrolysis, the suspension is taken into the sedimentation tank, and the solid matter precipitated and filtered contains Ca (H ₂ P0). ₄ ) ₂ · 0, the solution after separating Ca (H ₂ P0 ₄ ) ₂ · H ₂ 0 is sent to the Ca ²⁺ clear solution storage tank to become a solution containing water-soluble Ca ²⁺ ;

2. Take a solution containing H ₂ S0 ₄ , KHS0 ₄ , K ₂ S0 ₄ , N3⁄4S0 ₄ (filter out the solids), and directly enter the S0 ₄ ² — storage tank to become a solution containing water-soluble SO/— ;

c. separately purifying the above solution containing water-soluble Ca ²⁺ and SO/-, preparing a Ca ²⁺ purification liquid and a S0 ₄ ² - purification liquid, and storing them separately;

 D_l, continuously preparing SO/-mixing liquid with dilute solution containing SO/- and SO/-purifying liquid;

D_2, continuously preparing a Ca ²⁺ solution by using a dilute solution containing Ca ²⁺ and a Ca ²⁺ purification solution;

E_l, continuously adding the SO/-containing compounding liquid and the Ca ²⁺ -containing compounding liquid to the whisker synthesizer, and controlling the mixed reaction product to contain an excessive amount of SO/-dilute solution and calcium sulfate Whiskers

 E_2, continuously transferring the product containing the excess SO/-diluted solution and calcium sulfate whisker into the aging thickener; e-3, the calcium sulphate whisker in the aging thickener is containing an excessive amount of SO /- aging under continuous conditions;

 E_4. After separating a part of the aged calcium sulfate whiskers from the aging thickener, an excessive SO/-thin solution is contained, and it is continuously sent to the storage reserve tank to form a SO/-diluted solution.

In the present embodiment, the solution is a Ca ²⁺ -free solution, and the SO / - ion concentration is in the range of 0. 05~0. 2mol / l, this solution is Reaction product: Ca (N0 ₃ ) ₂ + (H ₂ S0 ₄ , KHS0 ₄ , K ₂ S0 ₄ , N3⁄4S0 ₄ , MgS0 ₄ , (NH ₄ ) ₂ S0 ₄ water-soluble sulfate) is formed, and the product is Correspondingly, it is a jump containing a small amount of phosphoric acid, KN0 ₃ , N Chat ₃ , NaN0 ₃ , Mg (N0 ₃ ) ₂ , and the solution of generating HN0 ₃ can be returned to step a for acid hydrolysis of phosphate rock, and the remaining liquid is mainly used for two purposes. First, return to step d-1 to continuously prepare SO/-formulation liquid with SO/-diluted solution and SO/-purification liquid; second, as liquid product, further process into corresponding solid product.

 Therefore, the liquid product of this embodiment is mainly delivered from this outlet.

E_5, continuously separating from the thickener a solid-liquid mixture comprising both aged calcium sulfate whiskers and a dilute solution containing SO/-, and continuously feeding it into a calcium-enhancing Ca ²⁺ thickener; E_6, in the calcium-enhanced Ca ²⁺ thickener, continuously adjust the concentration of calcium ion Ca ²⁺ in the thickener with Ca ²⁺ purification solution, so that the calcium sulfate whisker is in a dilute solution condition containing calcium ion Ca ²⁺ excess Continuously aging, and continuously discharging the aged solid-liquid compound out of the calcium-enhancing Ca ²⁺ thickener;

f. Calcium sulphate whiskers from a calcium-enhanced Ca ²⁺ thickener, filtered and washed to form a wet product of calcium sulphate whiskers; a filtrate containing excess calcium ion Ca ²⁺ , separated and sent to a storage reserve tank to form A dilute solution of Ca ²⁺ is returned to step d-2 in succession. Example 5: The invention is used for the treatment of acid-containing wastewater to co-produce calcium sulfate whiskers

 Purpose of the implementation: When the steel pickling and rust removal, there is a large amount of water-soluble iron in the slag, and there are many metal ores such as scheelite to produce tungstic acid or tungstate, and also efflux calcium-containing wastewater. In an industry with a large amount of acid and a large amount of sewage, the present invention utilizes a method of co-producing calcium sulfate whiskers to eliminate such sources of pollution and greatly improve its economic efficiency. The chemical reaction formula is:

 For the pickling and rust removal industry:

Fe ₂ 0 ₃ + 6HC1 = 2 FeCl ₃ + 33⁄40 (5-1)

2 FeCl +3Ca (OH) ₂ = 2 Fe (OH) ₃ \ + 3 Ca Cl ₂ (5-2)

3 Ca Cl ₂ +3 H ₂ S0 ₄ = 3Ca S0 ₄ · 2H ₂ 0 Whisker + 6HC1 Formula (5-3 )

The resulting 6HC1 is then returned to pickling and rust removal, and the Fe(OH) ₃ solids are concentrated by filtration for the production of iron salts.

 Pretreatment with many metal ores with a large amount of acid, such as tungstic or tungstate made of scheelite, IJ:

Ca W0 ₄ +2 HC1 = H ₂ W0 ₄ \ + CaCl ₂ (5-4)

Ca Cl ₂ + H ₂ S0 ₄ = Ca S0 ₄ · 2H ₂ 0 Whisker + 2 HC1 Formula (5-5 ) Regenerated 2 HC1 returns to decomposed tungsten ore powder.

For pickling and rust removal, low-cost chemical by-products S0 ₄ and HC1 can be used. Pretreatment of metal ore can be based on the processing requirements without affecting the quality of metal products. Try to use low-cost by-product acid.

 Example process steps:

a, preparing a solution containing water-soluble Ca ²⁺ ;

Wastewater from pickling or rust-removing ore (containing water-soluble salts such as FeCl ₃ and CaCl ₂ ), enters the Ca ²⁺ preparation process, is converted and purified by Ca (0H) ₂ , and the suspension is separated and precipitated by Fe ( 0H) ₃ and solid impurities, the supernatant is filtered and sent to the Ca ²⁺ supernatant for storage to prepare a solution containing water-soluble Ca ²⁺ ;

 b. preparing a solution containing water-soluble SO/-;

H ₂ S0 ₄ (or industrial by-product dilute sulfuric acid) is placed in a settling tank to settle statically, and filtered to clean H ₂ S0 ₄ to send H ₂ S0 ₄ a storage tank prepared to be a solution containing water soluble so/

C, respectively, with the above purifying water-soluble Ca ²⁺ and SO / - solution, the decontamination liquid is made of Ca ²⁺ and S0 ₄ ² - cleaning fluid, respectively, and stored for later use;

 D_l, continuously preparing SO/-mixing liquid with dilute solution containing SO/- and SO/-purifying liquid;

D_2, continuously preparing a Ca ²⁺ solution by using a dilute solution containing Ca ²⁺ and a Ca ²⁺ purification solution;

E_l, continuously adding the SO/-containing compounding liquid and the Ca ²⁺ -containing compounding liquid to the whisker synthesizer, and controlling the product after the mixing reaction to contain an excessive amount of SO/-dilute solution and calcium sulfate Whiskers

 E_2, continuously transferring the product containing the excessive SO/-diluted solution and the calcium sulfate whisker into the aging thickener;

 E-3. The calcium sulfate whisker in the aging thickener is continuously aged under a dilute solution containing an excessive amount of SO/-;

 E_4, a dilute solution containing an excess of SO/- after a part of aged calcium sulfate whiskers is separated from the aging thickener, and continuously sent to a storage reserve tank to form a SO/-diluted solution.

 In this embodiment, the SO/-diluted solution is mainly returned to the step b to prepare a water-soluble SO/- solution, and the step d-1 is continuously formulated with a SO/-containing dilute solution and a SO/-purifying liquid. /—The solution is prepared.

E_5, continuously separating from the thickener a solid-liquid mixture comprising both aged calcium sulfate whiskers and a dilute solution containing SO/-, and continuously feeding it into a calcium-enhancing Ca ²⁺ thickener;

e_6, calcium Ca ²⁺ increase in the thickener, liquid is continuously purged with Ca ²⁺ Ca ²⁺ regulation of calcium concentration in the thickener, the concentration of Ca ²⁺ is preferably 0. 05~0. 2mol / l, of sulfuric acid Calcium whiskers are continuously aged under dilute solution containing calcium ion Ca ²⁺ excess, and the aged solid-liquid compound is continuously discharged from the calcium-enhancing Ca ²⁺ thickener; f, from calcium-enhanced Ca ^The calcium sulfate whisker of the ²⁺ thickener is filtered and washed to become a wet product of calcium sulfate whiskers; the filtrate containing excess calcium ion Ca ²⁺ is separated and sent to a storage reserve pool to form a dilute solution of Ca ²⁺ , the rest of the continuous return to step d-2.

In this embodiment, a part of the dilute solution of Ca ²⁺ fed into the storage reserve tank is separated, and the chemical composition thereof is mainly a regenerated acid solution, and the acid solution can be returned to the original pickling rust or acidolysis ore process. Continuing to use, theoretically, 1.3 tons of high-purity anhydrous calcium sulfate whiskers can be produced per ton of sulfuric acid (equivalent to pure H ₂ S0 ₄ ). It can be seen that the economic benefit of such wastewater recycling is very huge, and its environmental and social benefits are far greater.

 In this embodiment, the regenerated acid is supplied from this outlet.

Claims

Rights request A method for continuously producing calcium sulfate whiskers on a large scale, which comprises the steps of: a. preparing a solution containing water-soluble Ca ²⁺ ;  b. preparing a solution containing water-soluble SO/-; c. respectively purifying the above water-soluble Ca ²⁺ and SO/- solutions to prepare a Ca ²⁺ purification liquid and a SO/-purification liquid, and storing them separately;  D_l, continuously preparing SO/-mixing liquid with dilute solution containing SO/- and SO/-purifying liquid; D_2, continuously preparing a Ca ²⁺ solution by using a dilute solution containing Ca ²⁺ and a Ca ²⁺ purification solution; E_l, continuously adding the SO/-containing compounding liquid and the Ca ²⁺ -containing compounding liquid to the whisker synthesizer, and controlling the mixed reaction product to contain an excessive amount of SO/-dilute solution and calcium sulfate Whiskers  E_2, continuously transferring the product containing the excess SO/-diluted solution and calcium sulfate whisker into the aging thickener; e-3, the calcium sulphate whisker in the aging thickener is containing an excessive amount of SO /- Continuous aging under dilute solution conditions;  E_4, after separating a part of aged calcium sulfate whiskers from the aging thickener, an excessive SO/-dilute solution is contained, and sent to a storage reserve tank to form a SO/-diluted solution, and the remaining continuous return steps D-1 ; E_5, continuously separating the solid-liquid mixture including the aged calcium sulfate whisker and the dilute solution containing SO/- from the aging thickener, and continuously feeding it to the calcium-increasing Ca ²⁺ thickener ; E_6, in the calcium-enhanced Ca ²⁺ thickener, continuously adjust the concentration of calcium ion Ca ²⁺ in the thickener with Ca ²⁺ purification solution, so that the calcium sulfate whisker is in a dilute solution condition containing calcium ion Ca ²⁺ excess Continuously aging, and continuously discharging the aged solid-liquid compound out of the calcium-enhancing Ca ²⁺ thickener; f. Calcium sulphate whiskers from a calcium-enhanced Ca ²⁺ thickener, filtered and washed to form a wet product of calcium sulphate whiskers; a filtrate containing excess calcium ion Ca ²⁺ , separated and sent to a storage reserve tank to form A dilute solution of Ca ²⁺ , the remainder is continuously returned to step d-2. 2. The method for continuously producing calcium sulfate whiskers according to claim 1, wherein: the solution comprising the water-soluble Ca ²⁺ prepared in the step a is used for storing the Ca ^{2 of the} reserve pool. Prepared from a dilute solution of ⁺ The preparation of the solution containing the water-soluble SO/- described in the step b is prepared by using a dilute solution of SO/- stored in the reserve tank; The purification described in the step C is carried out by sedimentation, filtration, adding a special ion-removing reagent to form a special precipitate to be extracted and adsorbed, or by adding a substance for adjusting the pH to separate a certain type of ions. The pH-adjusting substance added is an ore and mineral powder containing phosphorus, or a limestone or lime milk containing calcium; The preparation of the SO/-mixing liquid described in the step d-1 includes adding an acid, a base, a salt, an organic substance or the like as a whisker controlling agent, so that the H ⁺ ion concentration of the SO/-mixing liquid is 20 mol/L ^10-12 mol/ between L; S0 ₄ ² - temperature regulating liquid formulation between -20~120 ° C, the concentration is preferably 0. 2~2 mol / L. The whisker controlling agent comprises various organic and inorganic compounds, wherein the inorganic acid is HC1, HNO ₃ , H ₃ P0 _{4 ,} etc.; the organic acid is formic acid, acetic acid, fatty acid, alcohol, etc.; the inorganic salt contains K ⁺ , water-soluble phosphates, chlorides and nitrates of cations such as Na\ leg+, Mg ² Α, Μη ²⁺ ; organic salts are water-soluble alkyl fatty acid salts, alkylbenzene sulfonates; bases contain 0Η_ The compound includes Mg(0H) _{2 ; the} organic substance is a water-soluble alkyl fatty acid salt, an alkylbenzene sulfonate, a polyvinyl alcohol, a polyacrylamide surfactant. The preparation of the Ca ²⁺ -mixing solution described in the step d-2 includes adding an acid, a base, a salt, an organic substance or the like as a whisker controlling agent, so that the H ⁺ ion concentration of the Ca ²⁺ compounding solution is 20 mol/L to ^10-12 mol. between / L; Ca ²⁺ - a temperature regulating liquid formulation between -20~120 ° C, the concentration is preferably 0. 2~2 mol / L. The whisker controlling agent comprises various organic and inorganic compounds, wherein the inorganic acid comprises HC1, HNO ₃ , P0 _{4 ,} etc.; the organic acid comprises formic acid, acetic acid, a fatty acid, an alcohol, etc.; the inorganic salt contains K ⁺ Water-soluble phosphates, chlorides and nitrates of cations such as Na\ leg+, Mg ² Α, Μη ²⁺ ; organic salts containing water-soluble alkyl fatty acid salts, alkylbenzene sulfonates; bases containing 0Η a compound of _, including Mg(0H) ₂ . The organic substance contains a water-soluble alkyl fatty acid salt, an alkylbenzenesulfonate, a polyvinyl alcohol, a polyacrylamide surfactant. O. 2〜3. 3 mol / L; The concentration of S0 ₄ ² - is preferably 0. 02~0. 3 mol / L;  The aging thickening machine described in the step e-2 comprises a thick unit composed of a split container, and respectively performs three functions of solid-liquid residence time, dense fluid discharge and clarified liquid discharge;  The diluted aging solution of the storage reserve pool described in step e-4 is preferably 0. 5~5 hours; Including liquid products containing water-soluble metal ions, and can supply such liquid products at any time; The calcium-increasing Ca ²⁺ thickener described in the step e-5 comprises a thick-packed unit composed of a split container, and respectively performs three functions of solid-liquid residence time, dense fluid discharge and clarified liquid discharge; E-6 in step with the Ca ²⁺ was purified by continuous regulation of the concentration of calcium ions Ca ²⁺ calcium thickener, the concentration of calcium ions Ca ²⁺ regulation in 0. 02~1 0 mol / l;. For 5〜5小时; The dilute solution of Ca ²⁺ in the storage reserve tank described in step f is a liquid product including water-soluble metal ions, and the liquid product can be supplied externally at any time. 3. The method for continuously producing calcium sulfate whiskers according to claim 1, wherein: the water-soluble Ca ²⁺ solution of step a comprises: 1) a solution containing water-soluble Ca ²⁺ prepared by decomposing a phosphorus-containing mineral with a mixed acid of HCl, HN0 ₃ , H ₃ P0 ₄ or any ratio thereof; 2) hydrated CaCl ₂ containing NaCl in an effluent process _; 3) a water-soluble Ca ²⁺ solution prepared by reacting a waste acid solution of a pickling and derusting industry with a calcium-containing compound such as lime milk, quicklime or limestone; 4) a water-soluble Ca ²⁺ solution prepared by pickling ore (mineral powder) of precious metal processing industry; 5) a water-soluble Ca ²⁺ solution prepared from an organic or inorganic spent acid and a calcium-containing compound; 6) containing water-soluble solids with Ca ^2+, and with an aqueous solution of a water-soluble Ca ²⁺ was prepared;  The solution containing the water-soluble SO/- described in step b includes:  1) an SO/-solution containing SO/-water-soluble solids dissolved in an aqueous solution; 2) a salt solution containing N3⁄4S0 ₄ component; 3) a salt solution containing the K ₂ S0 ₄ component; 4) an acid salt solution containing HS0 ₄ - component; 5) a solution containing H ₂ S0 ₄ ; 6) an SO/-containing ammonium salt solution formed by reacting a solid matter containing a CaS0 ₄ component with an ammonium salt containing a CO ₃ ² -component; 7) A water-soluble SO ₄ ² _ solution formed by reacting a solid matter containing a CaS0 ₄ component with a sodium salt containing a CO ₃ ² -component.